PLOWING THE SEA BOTTOM IN THE DARK OF THE NIGHT

My name is Farmer Jerry! My wife, Arlene, and I just spent the night, February 9, plowing the bottom of Caleta de la Isla. We dragged the 44 pound Bruce anchor back and forth across the bay for most of the night, powered by a steady 25 - 30 knots with gusts over 45. A boat in the next anchorage north reported 53 knots this morning on Amigo Net. It is now noon on the 10th and the wind is still gusting over 30 knots which it has been doing for over 24 hours.

Before all this wind started we had anchored in 11' of water with 110' of chain and 20' of 5/8" nylon rode tied to the chain for shock absorber. We sat OK for all yesterday afternoon and evening (15 - 30 knots). The forecast was for N to NE 15 - 25 knots with higher gusts. A wind from that direction would be coming directly off the land, about 200 yards from where we were anchored. The water between us and the beach was only a few feet deep and there would be no problem with waves building.

As the wind blew, actually gusted would be a better description since the steady wind was only about 15 knots but the gusts were twice that, we ate dinner and then watched a long DVD movie that didn't finish until 12:45 AM. While we watched the movie we were also watching the wind instrument on the nav station panel. It would stay above 33 knots for long periods of time while the boat would shudder and heel 10 degrees. We could tell that the steady wind speed was increasing and the gusts were significantly stronger than earlier in the afternoon. We also noticed that the boats motion was getting more erratic and we were rolling side to side more than normal. Unfortunately, we didn't think to question why the motion was different because we were too wrapped up watching "Snow Falling on Cedars."

But, we were not totally negligent. While watching the movie I went on deck about every 1/2 hour but didn't notice any change in position. When the movie ended I checked the depth guage and saw 23'. Whoa, It had been reading 13' at sunset. I keyed a waypoint into the GPS that corresponded to our position when we anchored six days earlier. The GPS said we had moved 0.16 miles (320 yards) to the southwest. I then set up the radar and found that yes indeed, we were headed back to La Paz, dragging the anchor behind us.

Actually we were dragging two anchors. Earlier in the day I had put the 22 pound Danforth off the stern to try to limit our swinging. So I had to retrieve that anchor before we could start the engine since we didn't know where the rode was, relative to the prop. I think the stern anchor was a big part of the reason the Bruce could not hold the bottom. With the Danforth digging in from the stern; the boat could not swing fast enough to stay head to wind as the wind shifted and Mirador ended up presenting way too much surface area to the wind.

I wrote a little program to calculate load on the anchor rode for various wind speeds. I took into account wind pressure adjusted for latitude, boat surface area, rigging surface area, junk on deck, surging due to gusts and waves, etc. It says that at 40 knots with the boat yawed 10 degrees the rode would feel about 1700 pounds but at 50 degrees it would feel 2700 pounds. The boat was getting 60 degrees to the wind at times and the gusts were over 40.

At 1:00 AM with no moon the only thing we cared about was hauling in the anchor and trying to motor back into sheltered water. We had moved far enough southwest that the point of land forming the NW corner of the cove was no longer protecting us from the big northerly swell that had a fetch of several hundred miles with over 12 hours of 25 plus knot winds. At the worst, we were only seeing four foot rollers but they were hitting us broadside.

By then it was so windy that we couldn't use the little FRS radios to talk from bow to cockpit 'cause they just picked up wind noise. This was a problem I had not anticipated. The anchor windlass, which can generate 1200 pounds of pull, was not able to pull us to windward and retrieve the chain. Arlene was behind the wheel trying to steer the boat toward the anchor and thus take some of the load off the chain. But, she had no way to see the chain to know which way to steer. With much loud shouting and running back and forth from the bow to the cockpit we were able to drive Mirador back over the anchor. Thank goodness for the anchor float with reflective tape which I could see with a spotlight from the bow. About 15 minutes of struggle enabled us to retrieve all the chain.

Then we had to motor back to our original anchor location at the head of the bay. The wind was gusting so much that even at 2600 RPM the bow was blowing off to the southeast. Arlene put the spotlight on the rock wall out there and saw that we were less than 100 yards from it. The other problem was that the big rollers from out in the Sea were coming into the part of the bay we were in, and were pushing us toward the rock wall. Full throttle and rudder finally moved us back to the north. But, my heart was in my throat for several minutes. The term "lee shore" takes on a whole new meaning at 1:45 AM, many miles from any possible help. You can see the rock wall to the far left of the picture below.

Then, using just the radar, I tried to find the way to the head of the bay and shallow water to drop the hook again.

The big problem was that the head of the bay contains less than 3' of water at low tide, even 200 yards offshore. But there was no radar target to use since the shoreline is just a gradually sloping sand beach. The GPS did provide a bearing and distance to the previous anchor spot but I was afraid to try to get that far into the potentially shallow water.

You can see in the picture to the left where the water changes from light blue to a slightly darker blue, in front of Mirador. At that point there is 6' of water at low tide.

I finally chickened out in 14' of water and dropped the anchor. It caught and held the first try, thank goodness for a Bruce. I let out all 110 feet of chain and put the 20' nylon anchor bridle on. By then it was 2 AM and the wind was steady in the mid-30s with big gusts.

Why do these things happen in the middle of the night with no moon? There was no ambient light since the closest electricity is in La Paz which is 21 miles South, behind the hills that form the south side of the bay.

I then used the MOB function on the Raytheon R20XX radar. It worked really well. The location where we were when I pressed MOB is marked by an asterick in a circle. The distance readout on the radar is the distance to the MOB location. I also placed a VRM ring so it just touched the rock wall cross wind from us (0.167 miles). We could then sit and watch the radar display to verify that we were not moving.

The only good news, and I kept trying to remind myself of this whenever panic would start to set in, was that the wind would just blow us out into deep water, the bad news was that it looked like 7' or 8' short period wind waves out there.

Arlene went to sleep about 3:30AM. I stayed in the cockpit and tried to sleep but had little success. The radar continued to show that we were not moving at all. About 4:00 the wind came up even more. (We later discovered out that our Windex wind indicator had been ripped off the mast head sometime during the night.) I was seriously concerned the Bimini was going to blow away. The wind was tearing the tops off the little wavelets coming from the head of the bay, about 1/4 mile upwind, and blowing that spray into the cockpit. The wind was also oscillating over 100 degrees so the boat was really shearing back and forth and heeling about 10 or 15 degrees when we got broadside to a big wave. Twice, the waves rolled me off the cockpit seat. But it was warm, crystal clear, and the stars were interesting.

I let out another 50' of nylon rode to try to lessen the impact of the big gusts which did sound like the proverbial freight train as they roared down the valley and out across the beach (see the picture below). At that point we had 170' of rode and chain out for a scope ratio of 9:1. About 4:30AM the radar told me we had again drifted 1000 feet from our 2 AM anchor position. I let out 50' more rode and started praying that the anchor would hold till there was some light in the sky. By 6:00 AM we had dragged another 600 feet and were in 25' of water again.

I woke Arlene and we struggled even harder, but at least we could see, to get the anchor up. By the time we could motor back to the head of the bay it was pretty bright out so I went all the way into 9' of water, as close as I could get to the North rock walls. We dropped the Bruce and it again caught and held the first try, in a steady 25 - 30 knots with higher gusts.

We are now sitting on 110' of chain and 60' of rode. I tied two 5/8" nylon lines to the 5/8" anchor rode and ran those lines to the bow cleats so we had a three point harness on the bow. We have been here for six hours now in gusts that peg the handheld meter (40 mph) for ten seconds at a time. We have not moved an inch.

THOUGHTS ABOUT THIS EVENT - from the perspective of five days rest

Caleta de la Isla probably gets more wind, and is much more gusty than many other anchorages.

The cove is at the mouth a canyon, as you can see in the picture to the left, that runs several miles to the NE, back to a 2000' peak. I suspect the valley acts as a funnel for the NE wind coming over the mountain.

We thought about moving to another anchorage when they started forecasting the wind but we didn't know which anchorage might be better, or worse.

Why didn't I put out the Fortress FX55 which is our storm anchor?

I was not sure it would find any grip in the light sand on the bottom. The orginal forecast for wind did not predict any significant increase over the winds we had seen all day. Since the Bruce had been holding for six days I was confident it would continue to hold. Two days after this situation we moved the boat a little further off the beach because we were experiencing a series of minus tides where the anchor would be in only 5' of water. I was afraid the wind would switch to the west and blow us into the shallows.

When I tried to retrieve the Bruce anchor at a very low tide I found it completely buried into the hard material under the loose sand. I am confident the anchor would have held if it had been there orginally.

We reanchored in 11' of water, about where we were when the Big Blow started, and found that the Bruce would only hold 1800 RPM in reverse which is equivalent to about 400 pounds of force on the rode or about 20 knots wind yawed at 10 degrees. I swam out to the anchor and had Arlene run the engine in reverse at slowly increasing speeds. I could see the poor 'ole Bruce try to dig into the hard bottom under the 4" of sand but it just kept skipping off the hard under surface. I don't know why the Bruce dug in once but not the second time.

We then put out the big Fortress in the same location. It quickly buried itself in the hard stuff under the sand and held 3200 RPM in reverse with no movement at all. (3200 RPM is about 950 pounds of force or about 40 knots yawed at 10 degrees).

So, we are going to start using the Fortress much more frequently.

I had dove on the Bruce several times during the days before the Big Blow. Each time I noted that only one fluke was buried and it was partially on it's side. I should have been suspicious of it's ability to hold when dug in at that attitude.

Putting out the stern anchor was a bad idea. We need to make a riding sail to reduce the shearing. We are also going to try a Pardey type of bridle arrangement from the stern cleat to the anchor rode to try to hold the stern at a fixed angle to the wind.

I should have let out a lot more scope much earlier in the evening. Our orginal 130' of chain and rode gave us only 7:1 scope when the tide brought the water depth up to 14' (the bow roller is 4' off the water). I think another 60' of rode would have made a big difference. The 5/8" nylon rode will stretch 20% in the big gusts, thus providing almost 16' of shock absorber.

We should have set up the GPS with an anchor dragging alarm. Our Garmin 128 GPS reports an average accuracy of +/- 12' when Selective Availability is turned off. If we set the alarm to go off at 0.02 miles (120') we would have known about the dragging before we ended up in deep water where we were exposed to the Sea of Cortez rollers.

We should have set up the deep water anchor alarm on the depth sounder. We should have had the alarm set for 16' so that as we drifted into deeper water we would have heard the alarm.

We should have been much more curious when the boats motion changed so dramatically while we were watching the movie. We should have determined why we were suddenly feeling the effects of rollers we had never felt before.

Now I remember the expression "Pride cometh before the fall" - I had gotten very confident in our anchoring skills. That confidence had led to a certain amount of complacency; no alarms, not enough scope, not checking position often enough. Now my confidence is a little more reasonable, I did not sleep well the next two nights and I did use the anchor alarms.